Electronic discharge device



Sept. 24, 1946. P. SPENCER ELECTRONIC DISCHARGE DEVICE Fil ed July 14, 1945 v VENTOIE,

FLRC/ L Spins/MK 5 ggw/L a Z/"M Try Patented Sept. 24, 1946 means ELECTRONIC DISCHARGE DEVICE Percy L. Spencer, West Newton, Mass., assignor to Raytheon Manufacturing Company, Newton, Mass, a corporation of Delaware Application July 14, 1943, Serial No. 494,685

Claims. 1

This invention relates to an electronic discharge device of the magnetron type, and more particularly to the lead-in conductors providing the electrical connections and supports for the cathode and heater elements of such devices.

In devices of the type to which the invention relates, the cathode and its heater form a unitary structure which must be accurately positioned with respect to a plurality of anode faces. Inasmuch as it is desired to provide a magnetic field having its lines of force directed longitudinally of the combined cathode-heater structure and the cooperating anode faces, it is necessary that the lead-in connections for the cathodeheater structure be disposed laterally of the tube so as not to interfere with the means for imposing such magnetic field. Since the lead-in conductors also support the cathode-heater structure any vibration of the rods forming the conductors results in a corresponding vibration of the cathode-heater structure relative to the anode faces. Such vibration of the cathode-heater structure relative to the anode faces results in irregularities in the operation of the device and is particularly objectionable Where the device is used on an airplane, vehicle, or other place where the device is subject to vibration.

It is a primary object of the present invention to provide a lead-in structure for the cathode and heater elements which will support these elements with suificient rigidity to prevent vibration thereof without introducing additional elements that would complicate the structure or alter the characteristics of the tube.

The above and other objects and features of the invention will be made fully apparent to those skilled in the art from a consideration of the following detailed description taken in conjunction with the accompanying drawing in which the single figure represents a longitudinal sectional view of a magnetron provided with the improved lead-in connections constructed in accordance with the present invention.

Referring to the drawing, reference numeral l indicates an hermetically sealed envelope formed of a hollow cylinder of non-magnetic conductive material, such as copper. The hollow cylinder 2 is closed at each end by end caps 3 and 4 which are likewise of copper and which are hermetically sealed as by soldering, or otherwise, to the ends of the cylinder 2. The interior Wall of the hollow cylinder 2 has an annular projection 5 extending inwardly from the surface thereof, and a plurality of plates 6 extend radially and from the annular projection 5 to provide a plurality of anode faces adjacent a cathode structure 1.

The cathode structure 1 includes a conducting sleeve 8 coated exteriorly with an electron emissive substance. Insulating end plugs 9 and Ill are provided for closing the ends of the hollow conducting sleeve 8, and conducting pins 12 and I3 extend through and are supported centrally in each of the plugs 9 and ID. A heater I4 is provided on the interior of the hollow sleeve 8 and is connected at each end to the conducting pins 12 and i3. Conducting strips l5 provide an electrical connection between the conducting pin I2 and the sleeve 8 and also serve to retain insulating plug 9 Within the end of said sleeve. Retaining strips it serve to retain the insulating plug in in the lower portion of the hollow sleeve 8, but these strips are not electrically connected to the pin l3. Magnetic poles l1 and 18 are provided closely adjacent the end caps 3 and 4 for imposing a magnetic field extending parallel to the adjacent anode and cathode faces, and transversely to the direction of the electron flow therebetween. Openings l9 and 23 are provided in the lateral wall of th hollow cylinder 2 at points above and below the radial plates 3. A pair of conducting pipes 2| and 22 is provided with reduced end portions 23 and 24, which reduced end portions are threaded to screw into the openings [9 and 20 and are hermetically sealed therewith. Openings 25 and 2% through the reduced end portions 23 and 24 permit cathode and heater lead-in conductors 21 and 28 to pass therethrough with sufficient clearance to avoid electrical contact with the conducting pipes 2| and 22. Glass seals 29 and 30 are mounted on the outer ends of the conducting pipes 21 and 22 and hermetically sealed therewith. The seals 29 and 33 comprise outer tubular portions 3! and 32 'of substantially the same diameter as the outer ends of conducting pipes 2| and 22. The tubular portions 3| and 32 are of substantial length in order to provide insulation between the conducting tubes 2| and 22 and the outer ends of the conductors 21 and 23. Reentrant stems 33 and 34, extending back through the tubular portions 3| and 32, terminate in elongated beads 35 and 36 in which are sealed the conducting rods 21 and 28. The length of the reentrant stems 33 and 34, together with the elongated beads 35 and 36, is such that the beads 35 and 36 project into or are adjacent to the outer-ends of the conducting pipes 2| and 22.

In manufacture, exhaust tubulations are provided adjacent the outer ends of the seals 29 and 30 and after the tube has been exhausted these are sealed oil as indicated at 31 and 38. By providing the exhaust seals 31 and 38 toward the 3 outer ends of the tubular portions 3! and 32 at points remote from the beads 35 and 36, injury to the seals formed by these beads with the conductors 2'! and 28, due to the heating thereof in the process of sealing off the exhaust tubulation at 31 and 38, is avoided. Also, in the normal operation of the tube, the seals formed by beads 35 and 36 are kept cool by proximity to the copper conducting tubes 2| and 22 if the beads are adjacent the tubes, thereby avoiding injury to the seals due to excessive heating thereof in normal operation. Furthermore, by providing relatively long reentrant stems 33 and 34 so that the elongated beads 35 and 36 project into the outer ends of the conducting pipes 2| and 22 the vibration of the rods 21 and 28 is reduced to such a degree that it becomes negligible and no longer aifects the operation of the tube.

While I have herein described a preferred embodiment of the invention, other embodiments within the scope of the appended claims will be apparent to those skilled in the art from a consideration of the form shown.

What is claimed is:

1. An electron discharge device comprising an -'i envelope, a cathode-heater structure, a pair of lead-in conductors connected to opposite ends of said cathode-heater structure, providing supports therefor and extending transversely there-- of, a pair of conducting tubes projecting externally of said envelope, said lean conductors extending through said conducting tubes and out of contact therewith, glass seals for closing the outer ends of said conducting tubes, said seals having tubular portions projecting outwardly from said conducting tubes, and reentrant stems projecting back into the outer ends of said conducting tubes for sealing and supporting conducting rods therein.

2. An electron discharge device comprising an envelope, a cathode-heater structure, a pair of lead-in conductors connected to opposite ends of said cathode-heater structure, providing supports therefor and extending transversely thereof, a pair of conducting tubes projecting externally of said envelope, said lead-in conductors extending through said conducting tubes and out of contact therewith, glass seals for closing the outer ends of said conducting tubes, said seals having outer tubular portions and reentrant stems extending through said outer tubular portions to points adjacent said conducting tubes and terminating in elongated beads for sealing and centering said conducting rods therein.

3. An electrical discharge device comprising an envelope of conductive material, a combined cathode-heater structure positioned centrally within said envelope and extending longitudinally thereof, a plurality of plates of conductive material projecting inwardly from a portion of said envelope intermediate the ends thereof, said plates providing a plurality of anode faces adjacent said cathode-heater structure, said envelope providing end spaces at each end thereof beyond the ends of said plates, said cathode-heater structure comprising an outer conducting sleeve providing an active surface coacting with said anode faces, and a heater within said sleeve, a pair of lead-in conductors, each connected to one end of said cathode-heater structure and each extending transversely to the axis of said cathode-heater structure, one in each of said end spaces, a pair of conducting tubes sealed in said envelope and projecting externally thereof, said lead-in conductors extending through said conducting tubes and out of contact therewith, glass seals for said lead-in conductors at the outer ends of said conducting tubes, said seals having tubular portions projecting outwardly from said conducting tubes, and reentrant stems projecting back into the outer ends of said conducting tubes for supporting said conducting rods therein.

a. An electrical discharge device comprising an envelope of conductive material, a combined cathode-heater structure positioned centrally within said envelope and extending longitudinally thereof, a plurality of plates of conductive material projecting inwardly from a portion of said envelope intermediate the ends thereof, said plates providing a plurality of anode faces adja cent said cathode-heater structure, said envelope providing end spaces at each end thereof beyond the ends of said plates, said cathode-heater structure comprising an outer conducting sleeve providing an active surface coacting with said anode faces, and a heater within said sleeve, apair of conductive members, one at each end of said cathode-heater structure and each projecting into one of said end spaces, one of said conducting members being electrically connected to both said sleeve and said heater, the other of said conducting members being electrically connected to said heater and insulated from said sleeve, a pair of lead-in conductors, each connected to one of said conducting members and each extending transversely to the axis of said cathode-heater structure, one in each of said end spaces, a pair of conducting tubes sealed in said envelope and projecting externally thereof, said lead-in conductors extending through said conducting tubes and out of contact therewith, glass seals for said leadin conductors at the outer ends of said conducting tubes, said seals having tubular portions projecting outwardly from said conducting tubes, and reentrant stems projecting back into the outer ends of said conducting tubes for supporting said conducting rods therein.

5. An electrical discharge device comprising an envelope of conductive material, a combined cathode-heater structure positioned centrally within said envelope and extending longitudinally thereof, a plurality of plates of conductive material projecting inwardly from a portion of said envelope intermediate the ends thereof, said plates providing a plurality of anode faces adjacent said cathode-heater structure, said envelope providing end spaces at each end thereof beyond the ends of said plates, said cathode-heater structure comprising an outer conducting sleeve providing an active surface coacting with said anode faces, and a heater within said sleeve, a pair of lead-in conductors one at each end of said cathode-heater structure and each extending radially therefrom through one of said end spaces, one of said lead-in conductors being electrically connected to both said sleeve and said heater, the other of said lead-in conductors being electrically connected to said heater and insulated from said sleeve, a pair of conducting tubes sealed in said envelope and projecting externally thereof, said lead-in conductors extending through said conducting tubes and out of contact therewith, glass seals for said lead-in conductors at the outer ends of said conducting tubes, said seals having tubular portions projecting outwardly from said conducting tubes, and reentrant stems projecting back into the outer ends of said conducting tubes and terminating in elongated beads for supporting said conducting rods therein.

PERCY L. SPENCER. 

